Why do you need a transitional solution? Why not Manhattan-Project the heck out of a purely renewable replacement? Coal is, for a variety of reasons, a terrible

Why do you need a transitional solution? Why not Manhattan-Project the heck out of a purely renewable replacement? Coal is, for a variety of reasons, a terrible stopgap. And nuclear buildout is too slow and expensive. For the cost of building significant new nuclear, we could build the new storage mechanisms, and all the solar/wind needed. Faster.